The present invention relates generally to signal analyzers and more particularly, to such analyzers which utilize the Chirp-Z transform.
Signal analyzers using the Chirp-Z transform have been well known, at least since R. M. Hays et al. presented SURFACE WAVE TRANSFORM ADAPTABLE PROCESSOR SYSTEM, pages 363-370 of the 1975 Ultrasonics Symposium Proceedings, IEEE Catalogue No. 75 CHO 994-4SU which is incorporated by reference herein. In applications such as radar, it is often necessary to analyze the component wave forms that are contained in a signal. Of course, each component wave form in the signal has its own frequency characteristic and a Chirp-Z signal analyzer operates over a predetermined signal bandwidth to present the signal's component wave forms in a frequency segregated time domain. Therefore, a Chirp-Z signal analyser actually separates the signal's component wave forms in time and permits each component wave form to be gated out or accessed with a time count in accordance with the relative position occupied by its frequency characteristic in the frequency segregated time domain. A Chirp-Z signal analyzer includes a sweeping local oscillator and a compression filter, each of which has a frequency parameter that must be predetermined in accordance with the signal bandwidth selected for analysis. For most signal analyzer applications, a very wide signal bandwidth is selected because it is desirable to capture as many component wave forms as possible for analysis. When performing such wide bandwidth analysis with conventional Chirp-Z signal analyzers, the sweeping local oscillator thereof must have a very fast sweep time to maximize bandwidth over which component wave forms in the signal are captured for analysis. However, such very fast sweep times result in very low resolution analysis due primarily to constraints resulting from the compression filter. If slower sweep times are utilized to obtain sufficiently high resolution analysis, the bandwidth is narrowed over which component wave forms in the signal are captured for analysis.